Effects of Ar/CF4 plasma etching on physicochemical and biological properties of smooth and sandblasted zirconia surfaces

Zirconia is increasingly recognized as a highly promising ceramic alternative to titanium-based implants due to its aesthetic and biocompatible properties. This study comprehensively investigates the effects of sandblasting and Ar/CF 4 plasma etching, individually and in combination, on the physicochemical surface properties and biological performance of zirconia. Zirconia specimens were prepared as machined and sandblasted groups, both subsequently subjected to Ar/CF 4 plasma etching. Surface wettability, roughness, and topography were characterized. Biological responses were assessed using SAOS-2 osteoblast-like cells for initial cell attachment, metabolic activity, differentiation, and focal adhesion formation. Macrophage inflammatory response and Streptococcus gordonii attachment were also evaluated. Wettability was monitored for 21 days under ambient storage. Ar/CF 4 plasma etching reduced contact angles on zirconia, producing highly hydrophilic surfaces with distinctive sub-micron features while preserving structural integrity, as demonstrated by FE-SEM analysis. Enhanced hydrophilicity, combined with micro-roughness from sandblasting and sub-micron structures from plasma etching, facilitated osteoblast proliferation and differentiation. Plasma etching did not provoke an adverse inflammatory response and resulted in diminished surface-attached bacterial biomass compared to titanium. Among the evaluated surfaces, sandblasted and plasma-etched zirconia (Zr-SL-etched) exhibited improved cell metabolic activity, a significant increase in ALP activity, a tendency for the highest extracellular matrix calcium deposition, and reduced attached bacterial biomass . Although wettability declined during storage across all surfaces, plasma-etched zirconia maintained lower contact angles than titanium. In conclusion, Ar/CF 4 plasma etching enhances zirconia’s biological performance by improving hydrophilicity and introducing sub-micron features, thereby supporting osteoblast responses and reducing bacterial attachment. Zr-SL-etched surfaces demonstrated the most favorable balance of biological responses, highlighting their strong potential for further development as implant surfaces. • Ar/CF 4 plasma etching markedly increases the hydrophilicity of zirconia implant surfaces. • Enhanced wettability and subtle sub-micron features promote osteoblast proliferation and differentiation. • Plasma-treated zirconia surfaces exhibit reduced bacterial attachment compared to titanium. • Among all modifications, the Zr-SL-etched surface offers the best balance between enhanced osteogenesis and minimal surface-attached bacterial biomass.